This project will provide genetic tools to the public research community by constructing a library of Drosophila strains (ultimately 14,000) in which each fruit fly gene has been tagged or disrupted with a single transposable element insertion. Approximately 40,000 new single P-element insertion strains and 13,000 new single piggyBac insertion strains will be constructed. The transposon insertion site in each strain will be identified by DNA sequencing, computational analysis and manual curation. A subset of about 4,000 lines will be selected, based on the criterion that the gene tagged by a transposon has not been disrupted in other strains in the collection. This subset of strains will be saved, balanced and transferred to the public stock center at Bloomington, Indiana, for distribution to the research community. During the proposed project period, we will increase the size of the current library to 10,000 strains, bringing 10,000/13,600 = 74 percent of Drosophila genes, regardless of phenotype, under experimental control. This number of new lines generated (4,000) is more than the number of all the Drosophila genes for which both molecular structure and mutant phenotype are currently known. While a wide range of biological and medical problems have already begun to be analyzed using Drosophila, far more is yet to come. These new tools will empower and advance productive research affecting most NIH Institutes and myriad human medical conditions. In strictly financial terms this proposal will benefit NIGMS as well as other NIH institutes, as equivalent strains will otherwise have to be inefficiently generated under individual lab R01s at much greater expense.